Hi everyone,
I'm using the TPS63070 in my design to regulate a set of 4 AA batteries to a stable 4.95V.
The requirements are as follows:
Input: 2.5V - 7V
Output: 4.95V(±1.5%) @ 0.02A to 0.40A
Design specifications:
Capacitance on output: 76uF (3x22uF, 1x10uF) on bare PCB (~200uF total when integrated into product)
Inductor: LPS3015 @ 1.5uH
The issue:
- The output voltage is way below its set 4.95V (521k and 100k resistor) at both 200 ohm test load and no load equally. (The output voltage hangs around 1.2V for a sec until it heats up enough and moves around between 0.1V and 0.7V)
- The IC triggers the over current protection on my lab power supply and will makes the flux on the board smoke. If allowed to run for half a minute will begin to burn away the board (traces are lifting up etc.)
I've already tried a new IC in case the one I got was broken, but still the same behaviour. None of the traces are shorted to any other signals, so that isn't the issue either.
Schematic (Near identical to datasheet):
Board layout:
Obviously the board design could've been a bit nicer, but right now I don't fully understand why this setup is enough for the chip to pretty much self-destruct.
(The 5VCC line right after goes into a connector, not much later in this picture. The total 5VCC line is less then 6cm long)
Just a case of a faulty batch from mouser, or is my design severely flawed? Thanks
